1. Field of the Invention
The present invention relates to a display device; particularly, the present invention relates to a display device having different curvature design.
2. Description of the Prior Art
With the development of the display technique, in addition to improving size and display quality, the appearance of display devices is also changed, such as curvature display devices. Comparing to planar type display devices, curvature display devices not only can be produced to have a larger size under the same width, but also can provide better viewing effect. For example, a TV screen can be produced in a concave shape, so that when users are watching TV, difference among distances from eyes to every location on a concave shaped TV screen is smaller than difference among distances from eyes to every location on a planar type TV screen. Each part of the display surface of a curvature TV connects line of sight at right angle or near right angle, forming the best viewing angle. Besides, the area of a curvature screen is larger than that of a planar screen under the same screen width, so that users can have a wider image.
Curvature displays can be made by utilizing an active lighting element (such as organic light emitting diode panels) or a passive lighting element (such as liquid crystal display panels). For traditional curvature display devices, when the liquid crystal panel is utilized to produce the curvature display, the liquid crystal panel is bent by an external force to form a curvature shape; however, the liquid crystal panel may have an uneven force distribution, generating stress-optical effect. Particularly, because stress is applied to the curvature shape of the display panel, refraction index along the maximum principal stress direction and that along the minimum principal stress direction are different, so that a slight phase difference exists between the maximum principal stress direction and the minimum principal stress direction when light passes through the display panel, and thus polarizer(s) cannot completely perform filtration, generating dark state light leakage. Because stress distribution is uneven on every part of the display panel, the amount of phase retardation on every part of the display panel is different, and the amount of light leakage on every part of the display panel is also different, resulting in uneven light leakage. Therefore, the structure of curvature display devices needs to be improved.